The invention relates generally to a steerable agricultural implement with adaptable wheel spacing.
A wide range of farm implements have been developed and are presently in use for tilling, planting, harvesting, and so forth. Seeders or planters, for example, are commonly towed behind tractors and may cover wide swaths of ground which may be tilled or untilled. Such devices typically open the soil, dispense seeds in the opening, and close the soil in a single operation. Seeds are commonly dispensed from seed tanks and distributed to row units by a distribution system. To make the seeding operation as efficient as possible, very wide swaths may be covered by extending wings on either side of a central section of the implement pulled by the tractor. Included in the wing assemblies are tool bars, row units mounted thereon, and support wheels. The wings and row units are commonly disposed in a “floating” arrangement during the planting operation, wherein hydraulic cylinders allow the implement to contact the soil with sufficient force to open the soil, dispense the seeds and close the soil. For transport, the wings may be elevated and folded forward to reduce the width of the implement.
Certain implements include steerable wheels configured to decrease a turning radius of the implement while in a transport position. As will be appreciated, steering the implement will induce a significant lateral force between the assembly supporting the wheels and the body of the implement. Consequently, certain implements employ a linkage positioned between wheel assemblies to resist the lateral loads. While the linkage may provide lateral stability, the additional structure raises implement weight and increases construction costs. Furthermore, because the linkage is positioned between the wheel assemblies, the spacing between wheel assemblies, wheel width, and/or wheel rotation angle may be limited.